Hydrogen production from bio-methane and bio-ethanol in catalytic membrane reactors

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Two kinds of membranes that were recently developed in our groups will be fine-tuned in their oxygen and hydrogen transport behaviour and used in catalytic membrane reactors for the transformation of (a) bio-methane and (b) bio-ethanol into hydrogen: oxygen-transporting perovskite-type and dual phase membranes and hydrogen-transporting nanoporous membranes. The project covers optimization of oxygen and hydrogen transport through the corresponding membranes, implementation of suitable catalysts, establishing kinetic compatibility between oxygen/hydrogen transport and the rate of the catalytic reactions and finally the testing of practice-relevant feeds of bio-methane and bio-ethanol.The concept of combining thermal water splitting with the partial oxidation of methane (POM) to synthesis gas, has been shown by us in a joint Chinese-German publication in Angewandte Chemie. However, the hydrogen production rate in this proof of principle was relative low since (i) no catalyst has been used for hydrogen production by water splitting, (ii) a hollow-fiber membrane reactor has been used which is not suitable for quantitative studies since the gas concentrations (and thus the driving force for permeation and catalysis) change in axial reactor dimension, and (iii) the Ni-based steam reforming catalyst did not allow the kinetically fast one-step catalytic partial oxidation of methane to synthesis gas. Therefore, we will study hydrogen production by combining water splitting and POM in a planar disc-shaped membrane reactor under consideration of kinetic compatibility by using novel catalyst in a new geometric arrangement which allows oxygen spill over.The concept of improving the hydrogen yield in steam reforming of ethanol via integrating hydrogen selective membranes has been positively proofed in recently studies. Nevertheless, these studies show that neither Pd (or Pd alloy) nor silica-derived molecular sieve membranes were stable in the steam reforming conditions, i.e. in the presence of steam, CO, and CO2. Our recently developed hydrophobic hydrogen-selective metal-organic framework (MOF) molecular sieve membranes provide an important opportunity to intensify the steam reforming reaction of ethanol in the form of a catalytic membrane reactor.